The Binary-900 comes with pre-covered balsa tail pieces. There hasn't been much attention to rounding the leading edges or tapering the trailing edges - they're basically 2mm planks.

The kit comes with small CA hinges, and the plans specify where they should go. This is all very standard stuff - cut slots into the edges of the control surfaces, insert the hinges and glue with thin CA. I made some marks on the edges of the tail pieces where the hinges go to help get everything lined up properly.

The only thing I did differently was that, after cutting a slot into my thumb rather than the rudder, I decided to make a quick jig for cutting the slots. I stacked enough post-it notes on the bench to raise an xacto blade to the center of the control surface, then clamped it down to create a nifty slot cutter. Check that the cutting depth is equal to half the size of the CA hinge - that way it will be properly centered when you assemble it.

After the tail pieces are joined, cut slots for the control horns and CA in place.

The vertical stabilizer of the Binary-900 is attached to the tailboom by cutting a 1" long slot into the end of the boom. The instructions call for drilling a hole through the boom, then using a file to cut the notch. Be very careful drilling the hole - it needs to be centered on the boom for the best finished strength. I started with a 1/32" drill in a Dremel Tool Drill Press, which made it relatively easy to get the hole centered in the boom. I then increased the drill size to 3/64, 1/16, then 5/64, which is a tad larger than the 1.8mm specified in the instructions. The hole serves as a strain relief, so a hair bigger than the width of the stab is OK.

I tried to use a Dremel tool with cutoff wheel to cut the slots. It worked OK to get the slots started, but it's really easy to make mistakes with that thing. After the slots were started, I used a small file to finish the job. This resulted in a nice, straight slot, and gave me time to test for a good fit.

The next step is to glue the tailboom to the wing mount pylon sleeves. Dry fit the boom to determine the positions of the sleeves, then rough up the boom with some sandpaper at the sleeve positions. To assemble, I mounted the pylons in the wing, flipped the wing upside down, inserted the boom, applied some 20min epoxy and slid the boom to the final position.

This step determines the relative alignment of the wing and tail, so it is very important to get everything square. I dry-fitted the vertical stabilizer into my new slot and used a square to get it perfectly vertical. This should get the tail/wing alignment just right. You also need to verify that the boom is square to the wing by measuring the distance from the wingtips to the end of the boom. In my case, I was just a hair off, so I nudged the boom to one side while the epoxy cured. There is tiny bit of slop in the sleeves, and was sufficient to fix my alignment problem.

Let it cure, and then we can move on to the next step: mount the boom into the fuselage.

Just got mine today... Wings are made of foam core covered with very light fiberglass.

Hey, LittleG - have you started building yours yet?

The bit I'm pondering at the moment is how to route the tail control lines. Harry says they should be run outside the boom, but that means holes in the back of the fuse and through the bulkhead. Not too big a deal, but I'm trying to concoct a clever way to get all the holes accurately aligned to minimize drag on the lines.

With the holidays over, full-time work has invaded my schedule again. I'm only able to spend a little time on the build in the evenings. All that's left is to mount the tail and install the radio gear!

Haven't started building it yet. Like you, I've been busy with work as well.

Quote:

Originally Posted by pivlrs

Hey, LittleG - have you started building yours yet?

The bit I'm pondering at the moment is how to route the tail control lines. Harry says they should be run outside the boom, but that means holes in the back of the fuse and through the bulkhead. Not too big a deal, but I'm trying to concoct a clever way to get all the holes accurately aligned to minimize drag on the lines.

With the holidays over, full-time work has invaded my schedule again. I'm only able to spend a little time on the build in the evenings. All that's left is to mount the tail and install the radio gear!